Electrode and electrolytic condenser



July 17, 1956 J. B. BRENNAN 2,755,418

ELECTRODE AND ELECTROLYTIC CONDENSER Filed oct. 5. 1951 iNVENTOR ATTOR NE YS 2,755,418 ELECTRUDE AND ELECTROLYTIC CONDENSER Joseph B. Brennan, Cleveland, Ohio Application ctoher 5, 1951, Serial No. 249,841 6 Claims. (Cl. 317-230) This invention relates to electrode construction and to electrolytic condensers in general, especially to an anode electrode which is of greater area than the cathode associated therewith.

This application is a continuation-impart of my appli cation Serial No. 33,042 led June 15, 1948, now Patent No. 2,580,399, which in turn is a continuation-in-part of my application Serial No. 591,909 led May 4, 1945 and which is now abandoned. Such application is itself a continuation-impart of my previously copending application Serial No. 227,316 which matured into Patent No. 2,375,211 on May 8, 1945 and this patent had been based upon an application that was a continuation-in part of my previous Patents Nos. 2,104,918 and 2,280,789.

Heretofore, there have been various types of construction proposed for electrodes for electrolytic condensers and such constructions have generally been designed so as to provide as large an amount of surface area on the anode electrode as possible so as to increase the capacity of a given size electrolytic condenser.

The general object of the present invention is to provide a novel anode electrode construction for a condenser and to provide an electrolytic condenser having a high capacity for a given volume.

Another object of the invention is to provide an irnproved electrode which is of inexpensive, easily formed construction.

Another object of the invention is to provide electrodes wherein the anode is of about double the area of the cathode.

Yet another object of the invention is to substantially encompass a cathode by the anode in an electrolytic condenser.

A further object of this invention is to provide an electrolytic condenser in which one flattened, exible porous particulate electrode is spaced from and surrounded by a second ilattened flexible porous particulate electrode.

The foregoing and other objects and advantages of the invention will be made apparent as the specification proceeds.

Attention is now directed to the accompanying drawings, wherein:

Figure 1 is a transverse section through a pair of condenser electrodes embodying the principles of the invention;

Fig. 2 is a transverse section, to a reduced scale, through a portion of an electrolytic condenser made by use of the electrodes of Fig. 1;

Fig. 3 is a transverse section, similar to Fig. l, of a modication of the invention;

Fig. 4 is a transverse section of the electrodes of Fig. l with a terminal tab being shown connected to the anode;

Fig. 5 is an elevation of a strip used in making an anode of the invention;

Fig, 6 is a cross-section of another type of a partially shaped electrode of the invention; and

Fig. 7 is a section of the electrode of Fig. 6 when com pleted.

Reference will now be had to the details of the construction disclosed in order to describe the invention completely. The drawings disclose an electrode construction generally indicated by the numeral 1t) and such an assembly comprises an elongate, porous, metallic anode 1li, the lateral margins 12 and 13 of which are folded innited States Patent O ice wardly of the anode 11 to positions substantially parallel to the flattened center portion of the anode 11. ln actual physical form, the anode 11 would have a more irregular surface than is shown in the drawings and it also may be of less uniform thickness and resemble the electrode of Figs. 6 and 7. Fig. l clearly shows that the free longitudinally extending edges of the lateral portions or margins 12 and 13 of the anode are spaced transversely of the electrode assembly and this structure is preferred although, in some instances, it may be possible that the portions 12 and 13 may be overlapped or butted. While the folds in the anode 11 are shown as being made with the adjacent surfaces being at right angles to each other, it will be appreciated that in actual practice, these folded zones of the anode, which obviously will extend the length of the anode, may be of a more rounded contour. A cathode 14, usually of slightly less width than the folded anode 11, is received within an enclosure produced from the lateral margins 12 and 13 with the remainder of the anode. Conventional insulation strips, or spacers 15 and 16, usually made from paper, are positioned between the adjacent surfaces of the cathode lili and the anode 11 so as to prevent electrical contact therebetween and permit impregnation of the electrode assembly with electrolyte.

In making a condenser from the electrode assembly iti, the electrode assembly usually is helically or rather spirally coiled upon itself and prior to rolling or coiling the electrode assembly on itself, additional insulation or spacer strip 17 of conventional construction is associated with the electrode so as to separate portions of the anode which would otherwise be in direct contact after a coil is made from the electrode 10. ln some instances, it may be desirable to produce a stacked electrode from the electrode 1d by merely superimposing a plurality of short lengths of same with each of the terminal tabs in such a construction being connected to one of the electrode components of each short length of electrode in thc electrode stack.

Figs. l and 2 clearly being out that the anode l1 has approximately twice the external surface area of the cathode 14. inasmuch as the anode i1 is of a porous construction, ions may freely move through the anode when ilowing through the condenser, and the relatively large surface area of the anode for a given space for a condenser made therefrom, will provide a condenser having larger capacity than other types of condensers heretofore made.

The anode 11 is shown as made from porous metallic material adapted for electrode use, such as spray deposited aluminum sheet. Also, separate spacers are shown provided between the anode and the cathode, but it may be possible to provide an insulation or spacer coating directly on the surface or surfaces of the anode 11 and avoid the use of separate spacer elements. This type of an anode construction is disclosed and claimed in my copending application Serial No. 774,197, which is now abandoned. Use of such material in making the anode would facilitate the fabrication of the electrode it? and assembly of a condenser made therefrom.

While in the foregoing it is stated that the cathode is enclosed within the anode, it is within the concept of this invention to enclose the anode within the cathode. Thus, either of the electrodes of an electrolytic condenser may be surrounded by or enclosed by the other electrode.

in the foregoing, the outer electrode has been described as being folded about the inner electrode. I have found, however, that instead of such procedure in the construction of the electrode assembly, l can form the assembly by welding or otherwise joining the edges of two outer flat flexible porous particulate electrode strips disposed on each side of a similar inner electrode strip to form a composite outer electrode strip enclosing or surrounding the inner electrode strip.

Figure 3 shows a modification of the invention wherein an electrode assembly 2t) is disclosed in which an anode 2l is provided with lateral margins 22 and 23 that are folded inwardly of the anode and are superimposed on one surface of the anode. In this instance, the cathode 24 may be of the same width as that of the folded-in anode and the cathode is positioned externally of the anode Vwhereby a spacer strip 25 may be positioned intermediate the center portion of the anode 21 and the lateral marginal portions 22 and 23 thereof. A second spacer strip 26 is positioned between the outer surfaces of the adjacent portions of the anode and the surface of the cathode 24 which is thereadjacent. With an electrode assembly as shown in Fig. 3, an auxiliary spacer 27 would also be associated with the electrode before coiling the electrode upon itself or otherwise making a condenser from same.

While any conventional type of a terminal tab may be provided for the cathode 14, Fig. 4 shows a separate terminal tab 31 that is provided for the anode 11 and is secured thereto in a desired manner. In this instance, holes 32 are shown where the metal has been displaced for staking the anode 11 to the terminal 31. It will be noted that the holes 32 engage with both the base or center portion of the electrode 11 and also with the lateral margins 12 and 13 of the anode so as to facilitate current flow to and through the anode. If necessary, special recessed portions may be provided in the edges of the cathode 14 to facilitate bonding the anode 11 to the terminal tab 31 without contacting the cathode.

impregnation of the electrodes made in accordance with the teachings of the invention with electrolyte may be facilitated by making longitudinally spaced apertures in the fold zones of the anode. Figure shows an elongate porous metallic strip 41 which is to be used in producing an anode such as the anode 11, and this metal strip 41 is provided with a plurality of longitudinally spaced apertures or holes or slits 42 therein. These apertures 42 are made in two longitudinally directed rows, each of which is adjacent a lateral margin of the strip 41. The apertures 42 are so positioned that they are located in the fold zone produced in the strip 41 when turning or folding the lateral margins thereof inwardly of the strip so as to produce the folded lateral margins such as are shown at 12 and 13 in Figs. 1 and 2. Hence, when electrodes made therefrom are impregnated with an electrolyte, the apertures 42 greatly facilitate flow of the electrolyte to the enclosure produced by folding in the lateral portions of the anode. Longitudinally folded porous anodes made in accordance with the invention may be used without these apertures 42, if desired.

it will be seen that the specific manner in which the metal strips used in making the anodes of the invention are produced, is not material to the present application and that such strips, which are of a porous construction, may be produced in any desired manner. Likewise, as pointed out before, any suitable type of a spacer strip may be used and such strip may be integrally bonded to the anode strip, and in some instances, might be integral with the cathode, if desired. The electrodes of the invention are formed from porous metallic strips which are in the vicinity of .003-.GG9" in thickness and which .are several inches wide. The spacer strips normally are thinner than the metal strips.

Figures 6 and 7 show a relatively uniform thickness electrode 51 that is formed from a porous metallic base strip 52. The strip 52 is of the general shape of a broad isosceles triangle so that by folding the relatively thin edge sections of the strip longitudinally in on the center part of the strip a relatively uniform thickness electrode is produced. The strip 52 is of the type produced by spraying metal onto a base that is moved by a spray device. Usuallyth'e strip`52 would' be formed to provide a surface insulating coating before it is shaped to make the electrode 51 therefrom.

The electrodes of this invention are preferably of flexible, flat, porous, particulate metal construction and are electrolyte permeable.

While several embodiments of the invention have been disclosed herein, it will be appreciated that modification of these particular embodiments of the invention may be resorted to without departing from the scope of the invention as defined by the appended claims.

Having thus described my invention, what I claim is:

l. An electrolytic condenser comprising a rst electrode made from an elongate, flexible porous metal strip, the lateral edges of which are folded in on the remainder of the strip and lie substantially parallel thereto with the edges of the strip being juxtaposed, said electrode producing an enclosure strip, a flexible second electrode of less width than the folded electrode positioned within the enclosure formed thereby, and flexible spacer strips separating the adjacent surfaces of the electrodes from each other.

2. An elcctrolytic condenser electrode assembly coinprising a flexible, porous, electrolyte-permeable metallic cathode strip, a flexible porous electrolyte-perineable metallic anode strip positioned parallel with said cathode strip, one of said strips having its opposite edges extending laterally beyond the corresponding edges of the other strip and folded about the corresponding edges the other strip to embrace said other Strip, and porous electrolyte permeable spacer strips disposed on opposite surfaces of the inner strip to maintain the outer strip out of contact with the inner strip.

3. An electrolytic condenser electrode assembly coinprising an inner flexible porous electrolyte-permeable metallic electrode strip, a pair of outer flexible porous electrolyte-permeable metallic strips positioned parallel with the inner strip on each side thereof with the edges of the outer strips projecting beyond the edges of the inner strip, the corresponding edges of the outer s being joined together to form an envelope of the ou strips embracing the inner strip, and porous electrolyte permeable spacer strips disposed on opposite surfaces the inner strip to maintain the outer strip out of contact with the inner strip.

4. An electrolytic condenser comprising a pair of flexible electrodes, one of said electrodes being made from an elongate, porous metal strip, the latter longitudinal edges of which are at least partially folded in on the remainder of the strip and lie substantially parallel thereto in spaced relation thereto for a tube-like structure, the other flexible metal electrode being of substantially the same width as the folded electrode and positioned within the tube-like structure, and spacer strips separating the electrodes from each other, said electrodes and spacer strips being wound as a unit upon themselves to produce a spiral coil.

5. A condenser as in claim 4 wherein terminal tabs are secured to each of said porous electrodes, and said terminal tab for said folded electrode engages with both the center and the folded-in margins thereof.

6. A condenser as in claim 4 in which the outside electrode completely envelopes the inside electrode.

References Cited in the file of this patent UNITED STATES PATENTS 208,665 Muirhead Oct. l, 1868 1,526,564 Dnbilier Feb. 17, 1925 2,223,173 Haase NOV. 26, 1940 2,463,765 Grouse Mar. 8, 1949 2,470,826 McMahon May 24, 1949 2,504,178 Burnham Apr. i8, 1950 FOREIGN PATENTS 555,964 Great Britain Sept. 14, 1943 627,333 Great Britain Mar. 8, 1949 

